Vehicle body front structure

ABSTRACT

A vehicle body front structure includes a pop-up hood unit disposed on a front end portion of an enginehood of a vehicle body and configured to move upward above the enginehood by using a lift-up mechanism. The pop-up hood unit is deformable due to an input of an impact upon a collision with a target for protection. The pop-up hood unit is shaped as a plate that extends in a left-right direction of the vehicle body and has a plate surface having an inclination angle that is variable relative to a horizontal plane.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2018-109996 filed on Jun. 8, 2018; theentire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The invention relates to a vehicle body front structure which protects atarget for protection such as a pedestrian.

Conventionally there is known a kind of a vehicle body front structurewhich is disclosed in the patent document (Japanese Patent ApplicationLaid-open No. 2000-168473).

The patent document discloses an airbag system to protect a target forprotection such as a pedestrian. The airbag system includes an airbagwhich inflates to deploy in a range from the bumper upper surface of avehicle body to approximately the front end portion of an enginehoodwhen detecting or predicting a collision with the target for protection.The airbag absorbs and relieves an impact caused by a collision with thetarget for protection.

SUMMARY OF INVENTION

In the airbag in the vehicle body front structure of the patentdocument, however, a smaller volume of the airbag makes a deploymenttime shortened. Therefore, there is a problem that the airbag tends todeflate with an impact in case of a collision with the target forprotection and the airbag cannot appropriately absorb the impact on thetarget for protection in case of the collision. If the airbag cannotappropriately absorb the impact on the target for protection in case ofthe collision, there is a high possibility that the target forprotection is bounced rearward of the vehicle body. This is notpreferable.

The invention is directed to a vehicle body front structure whichappropriately absorbs an impact on a target for protection in case of acollision with the target.

An aspect of the present invention provides a vehicle body frontstructure. The vehicle body front structure includes a pop-up hood unitdisposed on a front end portion of an enginehood of a vehicle body andconfigured to move upward above the enginehood by using a lift-upmechanism. The pop-up hood unit is deformable due to an input of animpact upon a collision with a target for protection.

According to the present invention, a vehicle body front structureappropriately absorbs an impact in case of a collision with a target forprotection such as a pedestrian.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

FIG. 1 is a perspective view of a vehicle body front portion, whichillustrates a lifted hop-up hood unit and a deployed bag body of anairbag system, in a vehicle body front structure according to a firstembodiment of the present invention;

FIG. 2 is a schematic vertical section view illustrating a lifted hop-uphood unit and a deployed bag body;

FIG. 3 is a schematic plane view illustrating a deployed bag unit;

FIG. 4 is a partially sectional schematic front view which illustrates ahop-up hood unit and a bag unit of an airbag system in case of acollision with a target for protection such as a pedestrian;

FIG. 5 is a schematic plane view illustrating a flow of gas in the bagunit of the airbag system;

FIG. 6 is a perspective view of a vehicle body front portion whichillustrates a lifted hop-up hood unit and a bag body of a deployedairbag system, in a vehicle body front structure according to a secondembodiment of the present invention;

FIG. 7 is a perspective view of a vehicle body front portion, whichillustrates a lifted hop-up hood unit and a deployed bag body of anairbag system, in a vehicle body front structure according to a thirdembodiment of the present invention;

FIG. 8 is a perspective view of a vehicle body front portion, whichillustrates a lifted hop-up hood unit and a bag body of a deployedairbag system, in a vehicle body front structure according to a fourthembodiment of the present invention;

FIG. 9 is a partially sectional schematic front view illustrating ahop-up hood unit and a bag unit of an airbag system in case of acollision with a target for protection such as a pedestrian in a vehiclebody front structure according to a fifth embodiment of the presentinvention; and

FIG. 10 is a partially sectional schematic front view illustrating ahop-up hood unit and a bag unit of an airbag system in case of acollision with a target for protection such as a pedestrian in a vehiclebody front structure according to a sixth embodiment of the presentinvention.

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will be described in detail withreference to the accompanying drawings as appropriate. In the followingdescription, the same constituents will be denoted by the same referencesigns and overlapping explanations thereof will be omitted. Whendirections are discussed, such directions are based on front-rear,right-left, and upper-lower directions from viewpoints of a driver.

First Embodiment

As illustrated in FIG. 1, an automobile V provided with a vehicle bodyfront structure according to this embodiment includes an enginehood 1located at a front part of a vehicle body and covering the upper surfaceof an engine room, and a pop-up hood unit 10 located at the front endportion of the enginehood 1 with its front end portion configured to belifted above the enginehood 1. In conjunction with an airbag system 20to be described later, the pop-up hood unit 10 absorbs an impact causedby a collision with a target for protection such as a pedestrian(including a person on a bicycle or the like) (hereinafter simplyreferred to as the “pedestrian”).

The pop-up hood unit 10 is made of a metal and obtained by pressing asteel plate, for example. The pop-up hood unit 10 takes on a plate shapethat extends in a right-left direction of the vehicle body. The pop-uphood unit 10 is deformable due to an input of an impact in case of acollision with the pedestrian.

Here, a material of the pop-up hood unit 10 only needs to be capable ofabsorbing the impact on the pedestrian along with the deformation due tothe input of the impact in case of the collision with the pedestrian.Such a material may be a plastically deformable material, an elasticallydeformable material, or a combination of these materials.

The pop-up hood unit 10 is lifted above the enginehood 1 by apredetermined amount through a lift-up mechanism that includes supportrods 11 and a not-illustrated driving source configured to drive thesupport rods 11. A not-illustrated lock mechanism fixes the pop-up hoodunit 10 at a position lifted by the predetermined amount. Any of abouncing device adopting an electric motor or a spring force, andmoreover, a device of so-called a pyrotechnic type that ejects a gas bya reaction of a gas-forming agent may be used as the driving source.When a collision detection device 30 to be described later detects acollision with the pedestrian or predicts a collision with thepedestrian, the driving source is activated upon receipt of anactivation signal. Here, if a collision with the pedestrian is avoided,then the pop-up hood unit 10 may be retracted from the lifted positionto an initial position.

As illustrated in FIG. 2, the airbag system 20 is arranged below thepop-up hood unit 10. The airbag system 20 includes an inflator unit 21and a bag unit 22 to be deployed as an air bag. The bag unit 22 isfolded back and stored in the airbag system 20.

The inflator unit 21 is a component to eject the gas into the bag unit22. The inflator unit 21 is of a pyrotechnic type that applies thegas-forming agent. As illustrated in FIG. 3, the inflator 21 includesinflators 21 a to 21 c at space intervals in a left-right direction ofthe vehicle body. The inflator unit 21 includes a central inflator 21 alocated at a central part in the right-left direction of the vehiclebody, a left inflator 21 b located on a left side of the vehicle body,and a right inflator 21 c located on a right side of the vehicle body.Each of the inflators 21 a to 21 c is ignited by an instruction from thecollision detection device 30 to be described later, and ejects the gasaccordingly.

Note that the airbag system 20 includes a not-illustrated controller forcontrolling the order of ejection and amounts of ejection of the gasfrom the inflators 21 a to 21 c. A control unit 32 (see FIG. 1)constituting a part of the collision detection device 30 is connected tothe controller, whereby the controller controls ignition of theinflators 21 a to 21 c based on signals sent from the control unit 32.Details of the collision detection device 30 will be described later.

Here, the inflator unit 21 may employ, instead of the pyrotechnic typeof an inflator, another type (a hybrid type) of an inflator configuredto eject an inflation gas by breaking a bulkhead of a high-pressure gascylinder filled with a high-pressure inflation gas with gunpowder or thelike.

As illustrated in FIG. 1, the bag unit 22 is deployable in such a way asto cover the enginehood 1 almost entirely. As illustrated in FIG. 2, thebag unit 22 is deployed on the enginehood 1 through an opening 5 that isdefined at the front end portion of the enginehood 1 with the liftedpop-up hood unit 10. In this case, the bag unit 22 is guided by a lowerrear edge part 12 of the pop-up hood unit 10 and a portion in thevicinity thereof and is deployed continuously behind the pop-up hoodunit 10. In other words, the pop-up hood unit 10 and the bag unit 22collectively function as a single continuous impact absorption unit.

As illustrated in FIG. 3, the bag unit 22 includes multiple bags intowhich the bag unit is divided back and forth and right and left, and isformed into a symmetric structure. Specifically, the bag unit 22includes bags 23 a to 23 i to be mainly deployed on the enginehood 1,and left and right upright bags 23 j and 23 k to be mainly deployedupright on left and right fenders 3 a and 3 b. The bags 23 a to 23 i aswell as the left and right upright bags 23 j and 23 k are connected toone another by using a sheet member 25.

Each of the bags, 23 a, 23 d to 23 i as well as the left and rightupright bags 23 j and 23 k takes on a spheroidal shape in an inflatedstate. Meanwhile, each of the bags 23 b and 23 c adjacent to the bag 23a located at a central part of a front end takes on a spherical shapewith a small diameter in an inflated state.

Each space surrounded by the bags adjacent to one another is formed intoeither a void 25 a substantially in a rhombic shape or a void 25 bsubstantially in a triangular shape. These voids 25 a and 25 b areintended to catch and hold the head, shoulders, waist, as well as elbowsand other joints of a pedestrian H.

The bag 23 a is located at the central part of the front end of theenginehood 1 and is arranged such that its longitudinal axis is orientedin the right-left direction in plan view. The gas flows from the centralinflator 21 a provided to the airbag system 20 into the bag 23 a. Thebag 23 b is located on the left side of the bag 23 a while the bag 23 cis located on the right side of the bag 23 a.

The gas flows from the left inflator 21 b provided to the airbag system20 into the bag 23 b on the left side of the front end. Meanwhile, thegas flows from the right inflator 21 c provided to the airbag system 20into the bag 23 c on the right side of the front end.

The bags 23 d and 23 e are located behind the left and right sides ofthe bag 23 a at the central part of the front end. Moreover, the bags 23f and 23 g are located behind the bags 23 d and 23 e, respectively. Eachof the bags 23 d and 23 e as well as the bags 23 f and 23 g is arrangedsuch that its longitudinal axis is oriented in the right-left directionin plan view. In addition, the bags 23 h and 23 i are located furtherbehind the bags 23 f and 23 g, respectively. The bag 23 h is arrangedsuch that its longitudinal axis is oriented diagonally leftward andrearward in plan view. On the other hand, the bag 23 i is arranged suchthat its longitudinal axis is oriented diagonally rightward and rearwardin plan view. The bags 23 h and 23 i are provided with discharge valves28, respectively, which are capable of discharging the gas.

The bags 23 a to 23 i as well as the left and right upright bags 23 jand 23 k are configured to communicate with one another throughcommunication paths 26.

The bags 23 b, 23 d, and 23 f that communicate with one another areconnected to a right side part of the upright bag 23 j on the left atintervals from a front side to a rear side thereof. The communicationpath 26 and a one-way valve 27 are provided at each connection of theupright bag 23 j. The one-way valve 27 is a valve that allows the flowof the gas only in a direction from any of the bags 23 b, 23 d, and 23 fto the upright bag 23 j.

The bags 23 c, 23 e, and 23 g that communicate with one another areconnected to a left side part of the upright bag 23 k on the right atintervals from a front side to a rear side thereof. The communicationpath 26 and the one-way valve 27 are provided at each connection of theupright bag 23 k. The one-way valve 27 is a valve that allows the flowof the gas only in a direction from any of the bags 23 c, 23 e, and 23 gto the upright bag 23 k.

Next, the collision detection device 30 will be described. Asillustrated in FIG. 1, the collision detection device 30 includes acamera 31 as a detection device facing forward through a frontwindshield W, and the control unit 32 as the controller disposed at anappropriate place inside the engine room or the like.

This camera 31 is an infrared camera. Nonetheless, the camera 31 mayinstead be a publicly known camera designed for ordinary shooting. Thecamera 31 shoots an image in front of the vehicle body through theenginehood 1 and thus detects a situation in front of the vehicle body.Alternatively, the camera 31 may adopt a camera to be used for anadvanced driver assistance system to assist a driver in a drivingoperation. The advanced driver assistance system is a system developedin order to automate, adapt, and strengthen a vehicle system for saferand better driving.

The control unit 32 has shot image data input from the camera 31 andpredicts whether or not there is a pedestrian who is liable to approachand collide with the front end portion of the enginehood 1 of theautomobile V in motion. In this case, the control unit 32 predictswhether or not there is the pedestrian liable to approach and collidewith the front end portion of the enginehood 1 by calculating a changein size (area) of the pedestrian at remote and close positions in frontof the enginehood 1 for each predetermined time period, for example.

When the control unit 32 predicts that there is the pedestrian liable tocollide with the front end portion of the enginehood 1, the control unit32 calculates as to what position in the right-left direction of thefront end portion of the enginehood 1 the pedestrian is likely tocollide, thereby predicting a colliding position. In addition, thecontrol unit 32 sends a drive signal to the electric motor of thelift-up mechanism in the pop-up hood unit 10, thus driving the electricmotor. Accordingly, the support rods 11 are lifted by the drive of theelectric motor whereby the pop-up hood unit 10 is lifted above the frontend portion of the enginehood 1 and fixed at that position.

Next, the control unit 32 detects that the pop-up hood unit 10 islifted, or in other words, that the opening 5 for deploying the bag unit22 is open above the airbag system 20. Then, the control unit 32transmits an ignition signal to the inflator unit 21. In this case, thecontrol unit 32 transmits the ignition signal to the component inflatorin the inflator unit 21 that corresponds to the predicted collidingposition. For example, if the predicted colliding position is located atthe central part of the enginehood 1, the control unit 32 firsttransmits the ignition signal to the central inflator 21 a correspondingthereto and then transmits more ignition signals to the left inflator 21b and the right inflator 21 c. Meanwhile, if the predicted collidingposition is located on the left side of the enginehood 1, the controlunit 32 first transmits the ignition signal to the left inflator 21 bcorresponding thereto and then transmits more ignition signals to thecentral inflator 21 a and the right inflator 21 c. In the meantime, ifthe predicted colliding position is located on the right side of theenginehood 1, the control unit 32 first transmits the ignition signal tothe right inflator 21 c corresponding thereto and then transmits moreignition signals to the central inflator 21 a and the left inflator 21b.

Here, when the predicted colliding position is located on the left sideof the enginehood 1, the ignition signals may be transmitted to the leftinflator 21 b and the central inflator 21 a in advance and then theignition signal may be transmitted to the right inflator 21 c later.Likewise, when the predicted colliding position is located on the rightside of the enginehood 1, the ignition signals may be transmitted to theright inflator 21 c and the central inflator 21 a in advance and thenthe ignition signal may be transmitted to the left inflator 21 b later.

Meanwhile, when the predicted colliding position is located at thecentral part of the enginehood 1, the ignition signals may betransmitted to the central inflator 21 a, the left inflator 21 b, andthe right inflator 21 c at the same time.

Here, a sensor to detect a collision may be provided to a bumper at thefront end of the vehicle body and the like, and the control unit 32 maydetect an actual colliding position by using a signal from the sensor.

Next, a description will be given of an operation in case of a collisionof the pedestrian H with the front end portion of the vehicle body.

First of all, when the automobile V is made drivable by turning on theignition and the like, the camera 31 of the collision detection device30 starts shooting the front of the vehicle body and the image data shotof the camera 31 is input into the control unit 32. Based on theinputted shot image data, the control unit 32 starts the prediction asto whether or not there is the pedestrian H liable to collide with thefront end portion of the enginehood 1.

When the control unit 32 predicts that there is the pedestrian H liableto collide with the front end portion of the enginehood 1, the controlunit 32 further predicts what position in the right-left direction ofthe enginehood 1 the pedestrian H is likely to collide. At the sametime, the drive signal is sent from the control unit 32 to the lift-upmechanism in the pop-up hood unit 10, and the pop-up hood unit 10 islifted. In other words, the pop-up hood unit 10 is lifted before thecollision by using the collision detection device 30.

Then, as the opening 5 is defined by lifting the pop-up hood unit 10,the bag unit 22 of the airbag system 20 is deployed on the enginehood 1through the opening 5. In this case, the control unit 32 sends theignition signal to one of the three inflators 21 a to 21 c located closeto the colliding position of the pedestrian H predicted by the controlunit 32. When the control unit 32 predicts that the colliding positionof the pedestrian H is located at the central part of the enginehood 1,for example, the ignition signal is transmitted to the central inflator21 a so as to deploy the bag 23 a at the central part of the front endto begin with. Meanwhile, when the control unit 32 predicts that thecolliding position of the pedestrian H is located on the left side ofthe enginehood 1, for example, the ignition signal is transmitted to theleft inflator 21 b so as to deploy the bag 23 b on the left side of thefront end to begin with. In the meantime, when the control unit 32predicts that the colliding position of the pedestrian H is located onthe right side of the enginehood 1, the ignition signal is transmittedto the right inflator 21 c so as to deploy the bag 23 c on the rightside of the front end to begin with. In the following, the case ofpredicting the central part of the enginehood 1 as the collidingposition of the pedestrian H will be described as an example.

If the pedestrian H collides with the front end portion of the vehiclebody after the prediction of the colliding position by the control unit32, the pedestrian H hits the lifted pop-up hood unit 10 and the pop-uphood unit 10 is deformed as a consequence (see FIG. 4 in which thepedestrian H is not illustrated). In other words, the pop-up hood unit10 can receive the colliding pedestrian H, thus appropriately absorbingan impact on the pedestrian H by the deformation of the pop-up hood unit10. In this case, the pop-up hood unit 10 is lifted from the front endportion of the enginehood 1 of the vehicle body, and therefore receivesthe waist of the pedestrian H which is close to the center of thegravity. In this way, the pop-up hood unit 10 effectively absorbs theimpact at the time of the collision of the pedestrian H.

Thereafter, the pedestrian H relieved from the impact by the pop-up hoodunit 10 moves onto the bag unit 22 deployed continuously behind thepop-up hood unit 10 (see FIG. 5). In this case, the pedestrian H movesonto the bag 23 a that is deployed from the pop-up hood unit 10 to thecentral part of the front end of the bag unit 22, and then onto the rearbags 23 d to 23 i while allowing the bag 23 a to absorb the impact. Whenthe bag 23 a located at the central part of the front end is squashed bya load of the pedestrian H in the process of this movement, the gasinside the bag 23 a is pushed out (escapes) through the communicationpaths 26 to the adjacent bags 23 b and 23 c in the smaller-diameterspherical shape located on the left and right sides, and is also pushedout (escapes) to the adjacent bags 23 d and 23 e in the spheroidal shapelocated at the rear and diagonally left and right of the bag 23 a.

Moreover, when the bag 23 a located at the central part of the front endis squashed by the load of the pedestrian H, the gas continuouslyejected from the central inflator 21 a flows from the bag 23 a throughthe communication paths 26 to the adjacent bags 23 b and 23 c located atthe left and right of the bag 23 a and to the adjacent bags 23 d and 23e located at the rear and diagonally left and right of the bag 23 a.Accordingly, internal pressures of the bags 23 b to 23 e adjacent to thebag 23 a are increased in advance. Thus, the impact is appropriatelyabsorbed in response to the movement of the load of the pedestrian H.Here, each of the adjacent bags 23 b and 23 c on the left and rightsides has a smaller volume than those of the remaining bags 23 d and thelike. Accordingly, the internal pressures of the bags 23 b and 23 c arerapidly increased. In this way, the impact is appropriately absorbedwhen the pedestrian H moves to the left or right from the bag 23 a atthe central part of the front end.

Then, the ignition signals are sent from the control unit 32 to the leftand right inflators 21 b and 21 c. Thus, the gas is ejected from theleft and right inflators 21 b and 21 c to the left and right bags 23 band 23 c of the front end. The ignition signals may be transmitted fromthe control unit 32 to the left and right inflators 21 b and 21 c at atiming before the bag 23 a at the center begins to be squashed by theload of the pedestrian H. Otherwise, the ignition signals may betransmitted by predicting a timing when the bag 23 a begins to besquashed, or by predicting a timing after the bag 23 a is squashed tosome extent.

The gas ejected into the left and right bags 23 b and 23 c of the frontend flows to the left and right upright bags 23 j and 23 k through thesideways communication paths 26. In this instance, if the load of thepedestrian H moves to the bag 23 c on the right side out of the adjacentbags 23 b and 23 c on the left and right sides, for example, the bag 23c is squashed by the load of the pedestrian H and the gas inside the bag23 c flows to the upright bag 23 k on the right side in such a manner asto be pushed out by the load of the pedestrian H. Moreover, even afterthe bag 23 c on the right side is squashed by the load of the pedestrianH, the gas continuously ejected from the right inflator 21 c flows fromthe bag 23 c through the communication path 26 to the upright bag 23 kon the right side whereby the upright bag 23 k on the right side iscontinuously inflated. Meanwhile, the gas ejected to the bag 23 b on theleft of the front end flows through the communication path 26 into theupright bag 23 j on the left side. Accordingly, the upright bag 23 j onthe left side is inflated.

In the meantime, the gas flowing from the bag 23 a at the central partof the front end to the bags 23 d and 23 e located at the rear anddiagonally left and right of the bag 23 a further flows to the rear bags23 f and 23 g and to the further rear bags 23 h and 23 i through thecorresponding communication paths 26. Meanwhile, part of the gas flowinginto the bag 23 d located at the diagonally left and rear of the bag 23a and to the rear bag 23 f flows to the upright bag 23 j on the leftside through the corresponding communication paths 26. In the meantime,part of the gas flowing into the bag 23 e located at the diagonallyright and rear of the bag 23 a and to the rear bag 23 g flows to theupright bag 23 k on the right side through the correspondingcommunication paths 26. Thus, the left and right upright bags 23 j and23 k are inflated.

In this case, when the load of the pedestrian H moves to the bags 23 dand 23 e located at the diagonally right and left and rear of the bag 23a, for example, the bags 23 d and 23 e are squashed by the load of thepedestrian H whereby the gas inside the bags 23 d and 23 e is pushed outby the load of the pedestrian H and flows into the rear bags 23 f and 23g and to the left and right upright bags 23 j and 23 k. Thus, the rearbags 23 f and 23 g and the left and right upright bags 23 j and 23 k arequickly inflated. Likewise, when the load of the pedestrian H moves tothe rear bags 23 f and 23 g, the bags 23 f and 23 g are squashed by theload of the pedestrian H whereby the gas inside the bags 23 f and 23 gis pushed out by the load of the pedestrian H and flows into the furtherrear bags 23 h and 23 i and to the left and right upright bags 23 j and23 k. Thus, the rear bags 23 h and 23 i are quickly inflated and theleft and right upright bags 23 j and 23 k are quickly inflated at thesame time. As the rear bags 23 h and 23 i are inflated, the pedestrian His inhibited from jumping into the front windshield W. The gas flowinginto the rear bags 23 h and 23 i is then discharged from the dischargevalves 28.

Note that the gas can communicate between the left and right bags 23 dand 23 e, between the left and right bags 23 f and 23 g, and between theleft and right bags 23 h and 23 i, through the correspondingcommunication paths 26, respectively.

When the pedestrian H moves onto the bag unit 22, the enginehood 1 isdeformed into a concave shape as illustrated in FIG. 4 due to a reactiveforce of the bag unit 22 receiving the load of the pedestrian H. As theenginehood 1 is deformed into the concave shape as described above, thebag unit 22 is also deformed into a concave shape in conformity to theshape of the enginehood 1. Accordingly, a force in directions indicatedwith arrows X1 in FIG. 4 acts on a bottom surface side of the bag unit22, and the left and right upright bags 23 j and 23 k are tilted indirections indicated with arrows X2 in FIG. 4 in such a way as to wraparound the pedestrian H who moves onto the bag unit 22 from both of theleft and right sides. In this way, even when the pedestrian H moves tothe right or left on the bag unit 22 after the collision, the left andright upright bags 23 j and 23 k serves as walls that avoid a secondcollision of the pedestrian H to fall down to the ground from the rightor left of the enginehood 1. Thus, the pedestrian H is appropriatelyprotected.

According to the above-described vehicle body front structure of thisembodiment, the pop-up hood unit 10 at the front end portion of thevehicle body is lifted above the enginehood 1 by using the lift-upmechanism at the time of the collision or at the time of prediction ofthe collision of the vehicle body of the automobile V with thepedestrian H. Thus, the pop-up hood unit 10 receives the pedestrian Hcolliding with the vehicle body and the impact on the pedestrian H isappropriately absorbed by the deformation of the pop-up hood unit 10. Inthis case, the pop-up hood unit 10 is lifted above from the front endportion of the vehicle body. Thus, the pop-up hood unit 10 receives thewaist of the pedestrian H located near the position of the center ofgravity of the pedestrian H colliding with the vehicle body, therebyeffectively absorbing the impact on the pedestrian H.

Here, when the pop-up hood unit 10 hits the pedestrian H around thewaist, the impact on the pedestrian H is appropriately absorbed wherebythe pedestrian H gets pushed by the pop-up hood unit 10 and thus movesforward. Accordingly, relative velocities between the vehicle body andthe pedestrian H come close to each other whereby the pedestrian H isless likely to be bounced back.

The pop-up hood unit 10 takes on the plate shape that extends in theright-left direction of the vehicle body. Accordingly, the pop-up hoodunit 10 receives the pedestrian H and gets appropriately deformed incase of the collision with the pedestrian H, thus appropriatelyabsorbing the impact on the pedestrian H.

As a consequence of lifting the pop-up hood unit 10, the opening 5 fordeploying the bag unit 22 is defined at the same time. In other words, agap formed by the lift of the pop-up hood unit 10 is used as the openingfor deploying the bag unit 22.

In the meantime, the lift of the pop-up hood unit 10 is carried out inconjunction with the deployment of the bag unit 22. Thus, the impact onthe pedestrian H is absorbed primarily by the pop-up hood unit 10 andthen absorbed secondarily by the deployed bag unit 22. Accordingly, theimpact on the pedestrian H is more effectively absorbed stepwise. Inaddition, reduction in manufacturing costs is achieved since it is notnecessary to separately provide a port for deploying the bag unit 22.

The bag unit 22 is guided by the pop-up hood unit 10 and deployedcontinuously with the pop-up hood unit 10. Hence, the bag unit 22 isdeployed smoothly and quickly on the enginehood 1. Moreover, the pop-uphood unit 10 and the bag unit 22 are continuous in the front-reardirection and are thus adapted to absorb the impact on the pedestrian Hmore effectively.

Since the collision detection device 30 is provided, the impact on thepedestrian H is predicted by using the camera 31 and the lift-upmechanism is activated with the signal from the control unit 32 beforethe collision so as to lift the pop-up hood unit 10 from the front endportion of the enginehood 1. In this way, the impact on the pedestrian His absorbed more reliably.

Second Embodiment

A vehicle body front structure of a second embodiment will be describedwith reference to FIG. 6. This embodiment is different from the firstembodiment in that the pop-up hood unit 10 is provided such that aninclination angle of its plate surface is variable relative to ahorizontal plane (not illustrated).

The pop-up hood unit 10 is lifted above the enginehood 1 by apredetermined amount through the lift-up mechanism that includes thenot-illustrated driving source configured to drive the support rods 11.In this instance, the pop-up hood unit 10 is bent forward by using anot-illustrated link mechanism or the like. In other words, the platesurface of the pop-up hood unit 10 is turned forward in the process ofbeing lifted and fixed. Here, the bag unit 22 is deployable through thedefined opening 5.

According to this embodiment, the inclination angle of the plate surfaceof the pop-up hood unit 10 is variable. Hence, the plate surface is setto an inclination angle with which it is possible to effectively absorbthe impact on the pedestrian H in accordance with the type of thevehicle, or in such a way that the plate surface faces the collidingpedestrian H, for example.

Here, the pop-up hood unit 10 may be configured to move (protrude) tothe front of the vehicle body while being inclined in the process ofbeing lifted and fixed. In this way, the colliding position on thepop-up hood unit 10 is shifted to the front of the vehicle body. Thus,it is possible to absorb the impact on the pedestrian H moreeffectively.

Third Embodiment

A vehicle body front structure of a third embodiment will be describedwith reference to FIG. 7. This embodiment is different from the firstand second embodiments in that the pop-up hood unit 10 is integrallyprovided with a front grill FG.

The pop-up hood unit 10 is provided continuously and integrally with anupper end portion of the front grill FG. The pop-up hood unit 10 is bentforward while being turned forward together with the front grill FGthrough the lift-up mechanism that includes the not-illustrated drivingsource configured to drive the support rods 11, and is thus lifted abovethe enginehood 1 by a predetermined amount. Then, the plate surface ofthe pop-up hood unit 10 is settled in the state of facing forward. Here,the bag unit 22 is deployable through the defined opening 5.

According to this embodiment, the pop-up hood unit 10 is turned andlifted integrally with the front grill FG. Hence, the plate surfacefaces the colliding pedestrian H and moves (projects) to the front ofthe vehicle body. In this way, the colliding position on the pop-up hoodunit 10 is shifted to the front of the vehicle body, which makes itpossible to absorb the impact on the pedestrian H more effectively.

Fourth Embodiment

A vehicle body front structure of a fourth embodiment will be describedwith reference to FIG. 8. This embodiment is different in that theopening 5 is defined by allowing the enginehood 1 to move as well.

A front part side of the enginehood 1 is lowered and a rear part sidethereof is lifted by a not-illustrated hood movement mechanism.Moreover, the entire enginehood 1 moves rearward whereby the rear partside overlaps the lower part of the front windshield W.

The rear part 14 of the pop-up hood unit 10 is mainly lifted by usingits front part as a fulcrum. The opening 5 is defined between theenginehood 1 and the pop-up hood unit 10 as a consequence of themovement of the enginehood 1 and the movement of the pop-up hood unit 10described above. In this case as well, the bag unit 22 is guided by thelower rear edge part 12 of the pop-up hood unit 10 and the portion inthe vicinity thereof and is deployed continuously behind the pop-up hoodunit 10.

Here, a rear end portion of the bag unit 22 includes an extending part22 a that covers part of the front windshield W. The extending part 22 ahas a bag shape which is inflated by the gas sent from the inflator unit21.

According to this embodiment, the relative movements of the pop-up hoodunit 10 and the enginehood 1 define the opening 5, thus deploying thebag unit 22 more quickly. In the meantime, the front part side of theenginehood 1 is lowered while the rear part side thereof is lifted so asto be bent forward, whereby the bag unit 22 deployed on the enginehood 1is also bent forward. As a consequence, the pedestrian H is less likelyto move rearward and the pedestrian H is appropriately protected on thebag unit 22.

Fifth Embodiment

A vehicle body front structure of a fifth embodiment will be describedwith reference to FIG. 9. This embodiment is different from the first tofourth embodiments in that the left and right upright bags 23 j and 23 kare provided with contact parts 23 j 1 and 23 k 1, respectively.

The contact parts 23 j 1 and 23 k 1 are integrally provided to lowerparts of the left and right upright bags 23 j and 23 k. The contactparts 23 j 1 and 23 k 1 are capable of coming into contact with the leftand right fenders 3 a and 3 b, and extend downward so as to cover atleast part of the left and right fenders 3 a and 3 b.

The above-described contact parts 23 j 1 and 23 k 1 come into contactwith the left and right fenders 3 a and 3 b, respectively, as aconsequence of inflation of the left and right upright bags 23 j and 23k with the gas. As the contact parts 23 j 1 and 23 k 1 come into contactwith the left and right fenders 3 a and 3 b, the left and right uprightbags 23 j and 23 k fall onto the pedestrian H due to reactive forcesthereof in directions indicated with arrows X2 in FIG. 9 in such a wayas to wrap around the pedestrian H who moves onto the bag unit 22 fromboth of the left and right sides.

According to this embodiment, even when the pedestrian H moves to theright or left on the bag unit 22 after the collision, the left and rightupright bags 23 j and 23 k serves as the walls that more reliably avoidthe second collision of the pedestrian H to fall down to the ground fromthe right or left of the enginehood 1. Thus, the pedestrian H isappropriately protected.

Sixth Embodiment

A vehicle body front structure of a sixth embodiment will be describedwith reference to FIG. 10. This embodiment is a modified example of theabove-described fifth embodiment.

The upright bag 23 j on the left side includes an inner bag 23 j 2, anouter bag 23 j 3, a lower tether (link) member 23 j 4, and an uppertether member 23 j 5. Meanwhile, the upright bag 23 k on the right sideincludes an inner bag 23 k 2, an outer bag 23 k 3, a lower tether member23 k 4, and an upper tether member 23 k 5. Since the upright bag 23 j onthe left side and the upright bag 23 k on the right side are symmetricto each other, the upright bag 23 j on the left side will be describedbelow in detail while the upright bag 23 k on the right side will beexplained as needed.

In the upright bag 23 j on the left side, each of the inner bag 23 j 2and the outer bag 23 j 3 extends in the front-rear direction on thefender 3 a on the left side, and has an oval cross-sectional shape. Thegas flows from the bag 23 b of the front end and from the bags 23 d and23 f (see FIG. 3) into the inner bag 23 j 2 on the left side through thecorresponding communication paths 26. Incidentally, the gas flows fromthe bag 23 c and from the bags 23 e and 23 g (see FIG. 3) on the frontright side into the inner bag 23 k 2 on the right side through thecorresponding communication paths 26.

In the upright bag 23 j on the left side, the inner bag 23 j 2 isconnected to the outer bag 23 j 3 through a communication path 26 a andthe gas flows from the inner bag 23 j 2 into the outer bag 23 j 3through the communication path 26 a.

The lower part of the outer bag 23 j 3 extends below the inner bag 23 j2 and is located on the side face of the fender 3 a on the left side.Meanwhile, a lower part of the outer bag 23 k 3 is located on the sideface of the fender 3 b on the right side.

The lower tether member 23 j 4 connects the lower end portions of theinner bag 23 j 2 and of the outer bag 23 j 3 to each other. The lowertether member 23 j 4 extends to cover at least part of the fender 3 a onthe left side. Incidentally, in the upright bag 23 k on the right side,the lower tether member 23 k 4 extends to cover at least part of thefender 3 b on the right side. The lower tether member 23 j 4 and thelower tether member 23 k 4 constitute the contact parts to come intocontact with the left and right fenders 3 a and 3 b.

The upper tether member 23 j 5 connects the upper end portions of theinner bag 23 j 2 and of the outer bag 23 j 3 to each other.Incidentally, in the upright bag 23 k on the right side, the uppertether member 23 k 5 connects the upper end portions of the inner bag 23k 2 and of the outer bag 23 k 3 to each other.

When the gas flows in and inflates the upright bag 23 j on the leftside, the lower end portion of the outer bag 23 j 3 comes into contactwith the fender 3 a on the left side through the lower tether member 23j 4. Meanwhile, when the gas flows in and inflates the upright bag 23 kon the right side, the lower end portion of the outer bag 23 k 3 comesinto contact with the fender 3 b on the right side through the lowertether member 23 k 4. When the above-described contact takes place, theleft and right upright bags 23 j and 23 k fall onto the pedestrian H dueto reactive forces thereof in directions indicated with arrows X2 inFIG. 10 in such a way as to wrap around the pedestrian H who moves ontothe bag unit 22 from both of the left and right sides.

According to this embodiment, even when the pedestrian H moves to theright or left on the bag unit 22 after the collision, the left and rightupright bags 23 j and 23 k serves as the walls that more reliably avoidthe second collision of the pedestrian H to fall down to the ground fromthe right or left of the enginehood 1. Thus, the pedestrian H isappropriately protected.

The vehicle body side structures according to the embodiments have beendescribed above in detail with reference to the drawings. It is to benoted, however, that the present invention shall not be limited only tothese embodiments and various changes are possible as appropriate withinthe range not departing from the scope of the present invention.

For example, the bag unit 22 does not always have to be of the symmetricstructure. In the meantime, a quantity and sizes of the bags may also beset as desired which may be different between the left side and theright side.

A quantity of the component inflators in the inflator unit 21 is notlimited to three. In this context, two or less, or four or moreinflators may be installed instead. In the meantime, when two or morecomponent inflators are provided in the inflator unit 21, amounts ofejection of gas may vary among the component inflators.

The one-way valves 27 may be provided to the communication paths 26 asappropriate. In this way, an impact attributable to the movement of theload of the pedestrian H is appropriately absorbed by the adjacent bags(such as bags 23 b, 23 c, and the like).

Each of the left and right upright bags 23 j and 23 k may be providedwith a gas discharge valve that discharges the gas to the outside whileretaining a predetermined internal pressure.

The camera 31 is used as the detection device. Without limitation to theforegoing, the pedestrian H may be detected by using a radar deviceinstead.

The present invention is applicable to a wide range of vehicles eachprovided with an energy storage, examples of which include a hybridvehicle, an electric vehicle, a fuel-cell vehicle, and the like.

Although the invention has been described above by reference to certainembodiments of the invention, the invention is not limited to theembodiments described above. Modifications and variations of theembodiments described above will occur to those skilled in the art, inlight of the above teachings. The scope of the invention is defined withreference to the following claims.

What is claimed is:
 1. A vehicle body front structure comprising: apop-up hood unit disposed on a front end portion of an enginehood of avehicle body and configured to translate upward above the enginehood byusing a lift-up mechanism, wherein the pop-up hood unit is deformabledue to an input of an impact upon a collision with a target forprotection, wherein the pop-up hood unit is shaped as a plate thatextends in a left-right direction of the vehicle body, and wherein thepop-up hood unit has a plate surface having an inclination angle that isvariable relative to a horizontal plane.
 2. The vehicle body frontstructure according to claim 1, further comprising: a bag unitconfigured to deploy on the enginehood of the vehicle body by a gas froman inflator, wherein the bag unit deploys on the enginehood through anopening that is formed at the front end portion of the vehicle body withthe pop-up hood unit moved upward.
 3. The vehicle body front structureaccording to claim 2, wherein the bag unit is configured to deploy incontact with the pop-up hood unit while being guided by the pop-up hoodunit.
 4. The vehicle body front structure according to claim 1, furthercomprising: a detection device configured to detect a situation in frontof the vehicle body; and a control unit configured to operate thelift-up mechanism by predicting a collision with the target forprotection based on a detection of the detection device.
 5. The vehiclebody front structure according to claim 1, wherein the pop-up hood unitis configured to translate upward above the enginehood by moving in asubstantially linear upward direction by using the lift-up mechanism. 6.The vehicle body front structure according to claim 1, wherein thelift-up mechanism comprises support rods that engage the pop-up hoodunit and are configured to be driven in a substantially linear upwarddirection so as to translate the pop-up hood unit in the substantiallylinear upward direction to dispose the pop-up hood unit upward above theenginehood.